set 3 MCQ Questions & Answers Detailed Explanation

Question : 1

A missile is launched with a velocity less than escape velocity. The sum of its kinetic and potential energies is

a) positive

b) negative

c) zero

d) may be positive, negative or zero

Question : 2

When you compress a coil spring you do work on it. The elastic potential energy

a) disappears

b) decreases

c) increases

d) remains the same

Question : 3

What is the correct equation for finding the acceleration?

a) a = ${v + u}/t$

b) a = u + vt

c) a = ${v - u}/t$

d) a = ${v + u}/2$

Question : 4

The energy of wind is

a) Electrical

b) Only kinetic

c) Only potential

d) Potential and kinetic both

Question : 5

Assertion :
A man gets completely exhausted in trying to push a stationary wall.
Reason :
Work done by the man on the wall is zero.

a) If Assertion is correct but Reason is incorrect.

b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.

c) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.

d) If Assertion is incorrect but Reason is correct.

Question : 6

1 kilowatt hour is equal to

a) 36 joule

b) 100 joule

c) 1 joule

d) 3.6 × 10³ kilo joule